The broad objective of this proposal is to examine how renal and mesenteric afferent nerves and prevertebral ganglia of the sympathetic nervous system contribute to the development of electrical activity in noradrenergic neurons which innervate the kidneys and mesenteric vasculature of guinea pig, rabbit and cat. The areas of particular interest are: a) possible synaptic input from renal afferents to prevertebral ganglia, b) modulation of renal afferent activity by noradrenergic neurons and angiotensin, c) possible synaptic input to prevertebral ganglia from baroreceptors located in the mesenteric circulation, and d) electrophysiological properties of neurons within prevertebral ganglia. The general method of approach will be the measurement in vitro, of electrical activity from renal afferent nerves and from neurons within prevertebral ganglia by both extracellular and intercellular recording techniques.